Fatigue behavior of SiC reinforced Ti(6AI-4V) at 650 °C

Axial, low cycle fatigue properties of 25 and 44 fiber vol pct SiC/Ti(6Al-4V) composites, measured at 650 °C, were compared with the fatigue properties of unreinforced Ti(6Al-4V) at the same temperature. A prior study of the fatigue behavior of this composite system at room temperature indicated that the SiC fiber reinforcement did not provide the anticipated improvement of fatigue resistance of this alloy. At 650 °C, the composite fatigue properties degraded somewhat from those at room temperature. However, these properties degraded more for the unreinforced matrix at 650 °C with the result that the composite fatigue strength was two to three times the fatigue strength of the matrix alloy. The reasons for this reversal are discussed in terms of crack initiation at broken fibers and residual matrix stresses.     

Thermodynamic study of liquid Cu-Mg alloys by vapor pressure measurements

Thermodynamic properties of liquid Cu-Mg alloys have been determined by magnesium vapor pressure measurements over pure liquid magnesium and liquid Cu-Mg alloys, in the composition range of 11 to 90 mole pct Mg between 845 and 1345 K, employing the transpiration technique. Based on the quadratic formalism suggested by Turkdogen and Darken for binary systems, analytical expressions have been derived representing integral and partial molar thermodynamic properties as functions of composition for the two terminal regions of suN Mg = 0 to 0.33 and 0.6 to 1.0. From the measured activity values of magnesium and copper, in the liquid alloys in equilibrium with solid intermetallic compounds, standard free energies of formation of Cu₂Mg(s) and CuMg₂(s) relative to pure solid components have been calculated and expressed as functions of temperature. Extractive Metallurgy Section, Metallurgy Division     

Design optimization of a biomass-fuelled steam-operated pistonless pump

The paper reports design optimization studies conducted on a novel steam-operated pistonless pump, fuelled by biomass. The pump delivers about 1.5 m³/h of water at a head of approximately 7 m (delivery head 2 m and suction head 5 m) consuming about 6–7 kg/h of biomass fuel (e.g. wood). It is useful for drinking water applications on farms in rural areas. The factors considered for the experimental optimization study are the geometric parameters of the main drum, the cooling chamber and the boiler. The optimum L/D ratio is 1.5, and the optimum capacity of the main drum is 140 litres. The optimum capacities of the cooling chamber and boiler are 20 litres and 1 litre, respectively.     

Keratoconjunctivitis associated with sialodacryoadenitis in rats

A high incidence of keratoconjunctivitis was observed in a closed colony of inbred Lewis/Wistar rats. Clinical signs including blinking, ocular discharge, circumcorneal flush, corneal opacity, ulceration, pannus, hypopyon, and hyphema were observed at about three weeks of age. Acute disease subsided by six weeks of age, but some lesions progressed to low-grade chronic keratitis. Six per cent of affected rats developed megaloglobus, which usually appeared by three weeks of age. Lesions included focal or diffuse interstitial keratitis, corneal ulceration, anterior synechia, and inflammatory exudate in the anterior chamber. A high incidence of lenticular and retinal degeneration was associated with megaloglobus. Most affected rats also had harderian dacryoadenitis. Sialodacryoadenitis virus (SDA) was recovered from nasal washes, but not from affected eyes. Serological evidence indicated that SDA virus infection was widespread in the colony.     

MOVE: A Distributed Framework for Materialized Ontology View Extraction

The use of ontologies lies at the very heart of the newly emerging era of semantic web. Ontologies provide a shared conceptualization of some domain that may be communicated between people and application systems. As information on the web increases significantly in size, web ontologies also tend to grow bigger, to such an extent that they become too large to be used in their entirety by any single application. Moreover, because of the size of the original ontology, the process of repeatedly iterating the millions of nodes and relationships to form an optimized sub-ontology becomes very computationally extensive. Therefore, it is imperative that parallel and distributed computing techniques be utilized to implement the extraction process. These problems have stimulated our work in the area of sub-ontology extraction where each user may extract optimized sub-ontologies from an existing base ontology. The extraction process consists of a number of independent optimization schemes that cover various aspects of the optimization process, such as ensuring consistency of the user-specified requirements for the sub-ontology, ensuring semantic completeness of the sub-ontology, etc. Sub-ontologies are valid independent ontologies, known as materialized ontologies, that are specifically extracted to meet certain needs. Our proposed and implemented framework for the extraction process, referred to as Materialized Ontology View Extractor (MOVE), has addressed this problem by proposing a distributed architecture for the extraction/optimization of a sub-ontology from a large-scale base ontology. We utilize coarse-grained data-level parallelism inherent in the problem domain. Such an architecture serves two purposes: (a) facilitates the utilization of a cluster environment typical in business organizations, which is in line with our envisaged application of the proposed system, and (b) enhances the performance of the computationally extensive extraction process when dealing with massively sized realistic ontologies. As ontologies are currently widely used, our proposed approach for distributed ontology extraction will play an important role in improving the efficiency of ontology-based information retrieval.     

A polypyrrole based gas sensor for detection of volatile organic compounds (VOCs) produced from a wheat bread

Early detection of contamination in food items is the current interest of research. Changes in concentration of volatile organic compounds emitted by the food items can provide valuable information about its contamination. Hence, a polypyrrole based gas sensor is developed for the detection and monitoring the organic volatiles produced from wheat bread during storage. Gas chromatography?Cmass spectroscopy results show that 1-heptanol, 1-pentanol, 1-octanol are the predominant volatiles produced from wheat bread during storage. Multifrequency impedance measurement technique is used to monitor the changes in electrical properties, mainly capacitance of the developed sensor over a frequency range 10 Hz?C2 MHz upon exposure to the above organic volatiles produced from the bread during storage of 120 h. Electrical property data show that the quantitative change in the above volatiles has influence on the change in capacitance of the developed sensor.     

Proposed modifications in ETSI GSM 06.10 full rate speech codec and its overall evaluation of performance using MATLAB

Today, the primary constrain in wireless communication system is limited bandwidth and power. Wireless systems involved in transmission of speech envisage that efficient and effective methods be developed (bandwidth usage & power) to transmit and receive the same while maintaining quality-of-speech, especially at the receiving end. Speech coding is a technique, since the era of digitization (digital) and computerization (computational and processing horsepower—DSP) that has been a material-of-research for quite some time amongst the scientific and academic community. Amongst all elements of the communication system (transmitter, channel and receiver), transmission channel (carrier of information/data, also called the medium) is the most critical and plays a key role in the transmission and reception of information/data.     

Application of fuzzy logic control system for regulation of differential pressure in Liquid Zone Control System

In this paper, fuzzy control scheme has been proposed for generating regulating signals to feed and bleed control valves, which are used in Liquid Zone Control System (LZCS) for maintaining constant pressure difference between gas outlet header and delay tank. The LZCS and the existing PI controller are briefly described. It is followed by the design of Fuzzy Controller. It consists of seven symmetric triangular input membership functions and output membership functions each. Mamdani implication has been used to infer output contribution from each rule. The centroid type of defuzzification method is employed to get the crisp output values. The fuzzy logic controller for feed and bleed control valves so designed has been validated by performing a variety of experiments on a full scale LZCS test setup at Bhabha Atomic Research Centre and its performance is analyzed and compared to that obtained with existing PI controller. In comparison with the existing PI controller, the fuzzy logic controller’s performance is superior in all cases considered.     

Early clinical outcomes after small incision lenticule extraction surgery (SMILE)

Purpose

Dry eye is known to impact on clinical outcomes after laser vision correction and the use of a newer ‘all femtosecond laser’ surgical approach may be associated with less impact on the ocular surface post-operatively. The purpose of this study was to evaluate the early clinical outcomes and tear instability after the first small incision lenticule extraction (SMILE) cases undertaken by three surgeons at a single site in the UK.